<!DOCTYPE html>
<html lang="zh">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>数据类型练习</title>
</head>

<body>
  <script>
    let a = true
    let b = 'true'
    let c = ''
    let d = null
    console.log(a, b, c, d)
    console.log(typeof c, typeof d)
    let e
    console.log(e, typeof e, undefined == null, undefined === null)
    function hi() {
      console.log('这是来自函数的信息')
    }
    let f = hi()
    console.log(f, typeof f)
    function hello() {
      // console.log('这是来自函数的信息')
      return 'hello'
    }
    let g = hello()
    console.log(g, typeof g)

    console.log(0.1 + 0.2 == 0.3)
    console.log(Number.MIN_VALUE, Number.MAX_VALUE)

    let h = 5
    let i = false
    console.log(isNaN(4), isNaN(i))

    let str1 = '单引号字符串'
    let str2 = "双引号字符串"
    let str3 = `反引号字符串`
    console.log(typeof str1, typeof str2, typeof str3)

    console.log(`字符串的内容可以动态生成，比如${h}`)

  </script>
</body>

</html>
